I have a video of my grandmothers life story years ago. Of course this was many years ago, before I had learned that I should have used a separate microphone. In a few places in the video others in the room make comments that come in loud.

So I need to filter out the background hiss, increase her volume and then lower the louder voices.

Regarding the hiss, Sound Forge 9.0 was the first of that line to include noise reduction.

You might check out Gold Wave. It has noise reduction. You can download a trial, which will probably do your whole project. The purchase price is only $50.

Make sure to edit a copy of the original, as Sound Forge and Gold Wave do destructive editing. (A save overwrites the file.)

For massaging the volume, I love using envelopes in Vegas. A quick way to normalize volume is with compression. A good trick for voiceovers is to double the track, compress one VERY hard, and leave the second track uncompressed or lightly compressed.

The heavily compressed track will be very even and full, but will sound dull and lifeless. Adding the original or lightly compressed track has sparkle, but can be thin and uneven. By combining the two, you get the best of both worlds.

Of course, this is a special project, so you'll probably be happy to adjust the volume word by word with the envelope. This will give the best results without pumping and other compression artifacts.

After you've hand tweaked the volume, the result might still sound thin. EQ can help. The 300 Hz area is the fundamental. That adjusts the body of the voice. The 1 kHz area is where the consonants live. Boost that for intelligibility. The 2.5 kHz area gives character. If the voice is nasal, push this down. If its dull and flat boost it up. From 5-15 kHz we get air and sparkle (and hiss.)

Next, you can add fullness by mixing in a small amount of a heavily compressed track. It adds fullness to vowels without adding boominess. Try 20:1 and -25 dB as the settings on the crushed track.

In case the original recording had clipping or distortion, Sound Forge has some tools for dealing with that. You would want to apply that up front, right after the noise reduction.

BTW, don't be too aggressive with the noise reduction. NR can produce an underwater, warbly sound, depending on the noise.

you actually might be able to fix this without going outside of Vegas. Maybe.

Go to the track header, go to Track EQ, run the audio and try each of the numbers (1 thru 4) and make running adjustments. Nothing is destructiveand you can go to 'default' to get it all back to where you started.
For example when I use either of my cameras there is a preamp hum (PD150/170).Either shotgun or hypercaroid, no matter.
I have a preset I did on the Track EQ that eliminates the hum but doesn't change the tenor of the audio itself.

I used to use a NR program and while it did a good job this is so much easier.
Try it, you might like it.

The audacity example is similar to what you would do in Sound Forge 9 or Gold Wave. In SF9, you highlight the noise area, click "capture noiseprint" and play it. You get to see the frequency of the noise, and can make a small number of adjustments. You can see the results here: 5. Canon 5D Mark II Audio Exposed - Noise on Vimeo

In Gold Wave (use it something like 50 times for free; purchase for $50), you highlight the noise, press Ctrl-C (copy), then choose "from clipboard" to set the noise print.

I haven't used Audacity, but the quality of GoldWave rivals that of SF9.

Jon, I'm finally getting around to trying this. I have Gold Wave Pro (SuperEZ Wave Editor Pro) trial installed. I've highlighted a small region, pressed the Ctrl+C, then opened the Noise Reduction Effect window. My problem is that I don't see the Preset "from clipboard" anywhere.

On my version, you highlight the noise, copy (Ctrl-C) the noise sample, select the entire range that you want to affect, then open the menu Effect | Filter | Noise Reduction. In the "Reduction Envelope" area, there's a selection for...

( ) Use Shape
( ) Use Current Spectrum
( ) Use Average
(*) Use Clipboard